The present invention relates to an improved, high loop density, woven back coil or ‘pin seam for use in joining the ends of papermaker’ and the like fabrics.
Woven fabrics, intended for use in either the forming, pressing or drying sections of paper making machines, are usually woven as a continuous strip which is converted into an endless loop by one of three methods:
(a) joining the opposed ends of the flat woven fabric with a permanent woven seam, such as is described, for example, in U.S. Pat. No. 3,366,355; or
(b) joining the opposed ends of the flat woven fabric by forming small loops in the opposed ends of the fabric and then interdigitating these loop ends during installation of the fabric on the paper making machine to form a passageway through which a pintle is inserted to form a hinge-type joint referred to as a pin seam, such as is described, for example, in U.S. Pat. No. 4,182,381; or
(c) joining the opposed ends of the flat woven fabric by forming small loops in each of the two opposed ends of the fabric, engaging each of the two sets of loops with a spiral coil and then interdigitating the two coils attached to the opposed fabric ends with each other to form a passageway through which pintle is inserted to form a hinge type joint, such as is described, for example, in U.S. Pat. Nos. 5,875,822; 6,065,505; 6,241,081; and 6,267,068.